Left centricular diastolic properties will be characterized in terms of early diastolic relaxation, diastolic pressure-volume and stress-strain relations, and patterns of left ventricular filling in patients with coronary artery disease and normal subjects. Diastolic function will be determined utilizing simulataneously recorded left ventricular angiographic volumes and high fidelity pressures, during diagnostic cardiac catheterization with the use of manometer tip catheters, and evaluated both in terms of available expressions and newly developed and/or modified algorithms. Left ventricular volumes will be determined non-invasively by radionuclide techniques. Pressure-volume analysis acquired non-invasively will then be correlated with that determined from contrast ventriculograms. In addition, diastolic distensile properties will also be characterized in terms of the ventricular filling rate. Ventricular pressures will also be computed from the first and second derivatives of the ventricular radionuclide time activity curve. Diastolic properties will also be examined by phase analysis using the Fourier fast transform to detect inhomogeneity of ventricular filling and its relation to altered diastolic function. The influence of reperfusion of ischemic myocardium upon left ventricular segmental and global diastolic properties will be evaluated in dogs which have undergone coronary thrombolysis with streptokinase, to determine whether increased myocardial stiffness contributes to the apparent preservation of systolic function. The patho-physiologic determinants of ventricular diastolic properties will be defined with particular regard to the role of extracardiac constraints; the role of peripheral arterial and venous circulatory dynamics upon cardiac systolic and diastolic function will be evaluated using external forearm plethysmography. The influence of positive and expiratory pressure ventilation upon left ventricular systolic and diastolic behavior will be investigated using both catheterization and non-invasive (echocardiographic) techniques. The influence of selected pharmacologic and physiologic influences - with particular reference to drugs whose effects may yield further insight into the physiological determinants of diastolic properties-on diastolic function will be determined.